Out of your mind, not out of your body知觉失常 并非身体移位
Aug 23rd 2007∣写于2007年8月23日
From The Economist print edition∣摘自经济学人杂志印刷版

Out-of-body experiences can now be created at will. Studying them sheds light on the nature of consciousness
体外的经历现在可被任意创造出来，而对此领域的研究有助于揭示知觉的本性

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“I HOPE to convince you that the time has come to take up consciousness as a strictly biological problem.” So rang out the opening address at the 1902 meeting of the American Association for the Advancement of Science (AAAS). However Charles Sedgwick Minot, the anatomist who said those words, jumped the gun. Consciousness is still an enigma. That it is created within the brain, scientists agree. That it is biology's most intellectually glamorous problem, they also concur. But what it is and how to find it remain unclear. Which is why, despite Minot's aspiration, its study has remained fodder for the rambling final chapters of cognitive-science textbooks and those at the dusky end of distinguished scientific careers. Few have dared take it on without a tenured position under their belts and a Nobel-prize medal around their necks.
“我希望能够说服大家，现在知觉问题要被视为是一种严格意义上的生物学问题。” 这是美国科学发展协会第1902次会议上的开场演讲词。然而，解剖学家查理斯?塞奇威克?迈诺特（Charles Sedgwick Minot）发表上述言论却为时尚早。知觉仍是一个不解之谜。科学家们一致认同知觉是从大脑内产生的，他们也同样承认知觉问题是生物学中最让人伤神的问题。但是，到底什么是知觉与如何发现知觉却尚不明了。因此，尽管迈诺特对此研究充满热忱，这还是使得该领域的研究被用作了认知科学课本中散漫的最终篇章的编写素材，并且充当了卓越科学生涯的衰败成果。在没有获得终身成就与诺贝尔奖章的情况下，没有人会踏足此领域的研究。

Recently, however, two youngish biologists without Nobel prizes have had a go. Working independently, Henrik Ehrsson of the Karolinska Institute in Stockholm and Olaf Blanke of Geneva University Hospital have been making inquiries into the notion of the bodily self—an important part of conscious experience.
然而最近，两位并未获得诺贝尔奖的颇年轻的生物学家却进行了此领域的研究。斯德哥尔摩的Karolinska研究中心的亨利柯?艾尔逊（Henrik Ehrsson）与日内瓦大学附属医院的欧拉夫?布兰科（Olaf Blanke）彼此的研究独立，但他们一直以来都在探究身体自我的概念，这是知觉体验的一个重要部分。

A sense of self is what makes a person distinct from his environment and from other people in it. It is also the thing upon which more complex layers of consciousness appear to rest. Dr Ehrsson and Dr Blanke try to divorce this perceived self from the perceiver's body—in other words to create that phenomenon so beloved of mystics, an out-of-body experience. And in two papers published in this week's edition of Science, the AAAS's house journal, they report their latest results.
自我意识是一个人区别于周身环境和该环境中其他人的根本东西，这种意识也是其它复杂层次的知觉存在的基础。艾尔逊博士与布兰科博士试着要将这种感知的自我与感知者本身的肉体相分离—也就是说，他们试图要创造出一种神秘家鼓吹的现象，即体外体验。在本周的美国科学发展协会的期刊《科学》中，他们的两篇论文阐明了他们的最新研究发现。

Reality is an illusion
现实是一种错觉

Dr Ehrsson's previous experiments have relied on an illusion called the rubber hand. This shifts someone's sense of owning his body away from his real hand to a prosthetic one. It works by allowing him to view only the rubber hand while both it and his real hand are stroked in synchronicity with one another. That coincidence is enough to fool the part of the brain that integrates inputs from different senses. The result is to redirect the subject's sense of self from his real hand to the rubber hand in a way analogous to the redirection employed by a ventriloquist when he makes his dummy “speak”.
艾尔逊博士在先前的实验中依赖于一种称为“橡胶手”的错觉。这种错觉会让一个本来感知拥有自己身体的人产生错误意念，即自己的天生的手变成的假手。该错觉的工作原理是让接受试验的人在橡胶手与他的天生的手同时摆动之时只能看到假手。这种重合足以愚弄进行各种感观信息整合的大脑部分。结果将把接受试验的人的本身自我意识进行转移—认为真手成了假手，这类似于一个口技表演人在让他的玩偶“说话”时所造成的感知转移。

Dr Blanke, by contrast, works with epileptics. Occasionally, people who suffer from epilepsy report having standard out-of-body experiences—the ones in which an individual looks down on himself from above. Five years ago Dr Blanke found he could induce such experiences at will in one such person by stimulating a particular part of her brain—the right angular gyrus—with an electric current. A small current made her feel as though she was sinking into her bed; a little more had her floating close to the ceiling or seeing her legs kicking towards her face.
相比之下，布兰科博士在癫痫患者身上进行了研究试验。偶尔，患有癫痫病的患者会说他们都有过通常熟悉的体外体验—在这种体验中，一个人仿佛会从高出俯视自己。五年前，布兰科博士发现他能够通过用电流刺激一个这类患者的大脑的特殊部位（右角脑回）而受感应，让她随意地进行这些体验。一股小小的电流能让她感觉到她好像是躺倒了自己的睡床里，将电流加大就会让她觉得自己漂浮到了天花板，或看到自己的双脚在踢自己的脸。

Once again, the part of the brain in question seems to be involved in integrating inputs from different senses. If this area is overstimulated during the electrical brainstorm that is an epileptic fit, the consequence is an out-of-body experience.
以上谈论的大脑部位似乎又一次地受到牵连，即该部位参与了整合各个感官所收集到的信息。如果大脑的这个部位在对癫痫病患者实行电击而造成脑猝变时过度地被刺激，那么结果就会让患者出现体外经历。

With these results in mind, both Dr Ehrsson and Dr Blanke wondered if they could design experiments that would induce complete out-of-body experiences in healthy volunteers. The answer, in both cases, was that they could.
在这些结果的引导之下，艾尔逊博士与布兰科博士同时在疑虑他们能否设计出一些试验，以引诱正常健康的志愿者出现体外经历。两位博士都给出了肯定的答复。

Dr Ehrsson did it by making his volunteers look at themselves from behind. He sat them in a chair and asked them to wear virtual-reality goggles, which work by projecting a picture in front of each eye. Behind the chair there were two video cameras adjusted so that they were at the level of the volunteer's eyes. The left-hand camera sent its picture to the left eye of the goggles; the right-hand camera sent its picture to the right eye. The subjects could thus see their own backs, in stereo, as though they were sitting behind themselves.
艾尔逊博士的做法是让他的志愿者们从背后看着他们自己。艾尔逊让他们各自坐在一张椅子上，并让他们戴上虚拟现实的护目镜，从这里面他们就会在他们每只眼睛前看到一张投影。在椅子的后面放置了两部调整好的摄像机，其高度保持着与志愿者眼睛的高度一致。左手边的摄像机会把拍摄到的影像发送到护目镜的左眼位，右手边的则发送到右眼位。这样，志愿者们就能够看到自己颇具立体感的背部，就好像他们正坐在自己的后面。

Dr Ehrsson then tested how touch is combined with vision to locate the self. When he tapped his volunteers on their chests at the same time as he tapped the air at chest-height below the cameras, they reported feeling that the core of their identity inhabited the camera's position. They were, in other words, out of their own bodies, and they considered their real selves—seen through the goggles—as another person. When, however, he prodded the chest and the air at different times, that illusion immediately dissolved.
接着，艾尔逊博士测试了触觉如何与视觉相联来定位自身。当艾尔逊在志愿者触及摄影机下方胸部高度的同时轻敲志愿者的胸部的时候，志愿者反映他们会感觉到他们身体的核心移位到了摄影机的位置。换句话说，他们感觉已经脱离了本体，并且在护目镜的作用下，他们却认为自己真正的身体成了另外一个人。然而，在艾尔逊博士刺激胸部与志愿者的动作发生在不同时时刻，那种错觉就会消失。

To make sure his volunteers were telling the truth, Dr Ehrsson surprised them after two minutes of tapping by swinging a hammer towards the camera. While he did this, his apparatus measured the level of sweat on the volunteer's skin. Since people sweat in response to a threat, that level is a good indication of what someone is really feeling. The sweat levels confirmed that volunteers really did feel threatened when the place they perceived themselves to be—the site of the camera—was attacked.
艾尔逊博士为了确定志愿者所说的真实确凿，他在轻敲胸部两分钟之后将一个锤子向着摄影机摆动，从而使志愿者们受惊。当他这样做的同时，他用设备检测到了志愿者皮肤上出现汗液的程度。由于人么在受到威胁时会流汗，因此汗液的程度会很好地说明他们的真正感觉。检测到的汗液程度也确定了一个事实，即当志愿者们认为他们所在的地方（摄影机的地点）被攻击时，他们确实感到自己受到了威胁。

Dr Blanke also asked his volunteers to wear virtual-reality goggles. But in his case the volunteer was standing and what he saw was one of three things. The first was a three-dimensional “avatar” of his own body—viewed from behind, as with Dr Ehrsson's experiment. The second was an avatar of a humanlike dummy, again viewed from behind. The third was a human-sized cuboid.
布兰科博士同样也是让他的志愿者们戴上虚拟现实的护目镜。但是在他的试验中，志愿者是站着进行的试验，而且这个志愿者看到了以下三种现象之一。第一种志愿者从背后看到自己身体的一个立体的“化身”，就像艾尔逊博士的试验结果一样。第二种是志愿者看到了一个人形假象，也是从背后看到的。第三种则是和真人大小一致的立方体。

Instead of tapping his volunteers, Dr Blanke stroked them with a paintbrush while, at the same time, the computer “stroked” the avatar with a virtual brush. Sometimes the strokes were in synchronicity, sometimes they weren't.
布兰科博士并没有轻敲他的志愿者们，而是用油漆刷触摸着他们；与此同时，电脑也用虚拟油漆刷触摸着人形化身。时而刷子的动作为同步，时而又不同步。

After each viewing the goggles went dark, so that the volunteer could see nothing at all. He was then pulled backwards a few steps and asked to return to his original position. If the avatar he had been watching was a cuboid, that was easy. It was also easy if the avatar had been humanlike (whether representing the volunteer or not) and the stroking had been asynchronous. But if the avatar had been humanlike and the stroking synchronous, then the volunteer always walked to the place where the avatar would have been standing had it been real. The volunteer, in other words, identified the avatar's former location as having been his own.
在每次的观看之后，护目镜就会变得一片漆黑，以让这个志愿者看不到任何东西。接着，他被向后拉了几步，然后再让他回到他最初的位置。如果这个志愿者一直所观看到的化身是一个立方体，那么回到原位就很容易；如果化身是和真人大小一致（不管这个化身是否代表志愿者）并且油漆刷与虚拟刷的动作为不同步，回到原位对志愿者来说也很容易。然而，如果志愿者看到的化身大小与真人一样，并且刷子的动作同步，那么志愿者就会走到化身一直站立的地方，就好像化身就是真实存在的。换句话说，志愿者认为化身的原先位置是他自己的。

Astral projection this is not. But it is a demonstration that one aspect of consciousness can be modified in a reproducible way. And that may be the key that unlocks the vault. For, if the methods Dr Ehrsson and Dr Blanke have come up with can be reproduced on volunteers inside a brain-scanner, then it might be possible to study the neurological network involved. Presumably this will include the right angular gyrus. But other components, as yet unknown, must surely be involved.
这不是星状体的影像。但是这却说明了人的知觉的某些方面能够通过创新的方式而得到改良，而且这可能是打开精神神秘宝藏的钥匙。因为，如果艾尔逊博士与布兰科博士所试验的方法能够用于大脑放射性扫描仪里对志愿者进行复制，那么这种方法就可能被用于研究相关联的神经网络组织。推测起来，这种研究将包括右角脑回。但是其它未知的部位肯定也要包含在内。

That will help to bring the study of consciousness into a mainstream in which the non-tenured can study it without receiving funny looks from their colleagues. And, who knows, it may one day lead Dr Ehrsson, Dr Blanke, or someone else whom they have inspired, to having one of those Nobel medals hung around his own neck.
那将让对知觉的研究成为主流研究领域，这样非业内人士在研究时也不用担心同时会向他扮“鬼脸”。此外，世事难以预料，也许此研究能让人把一块诺贝尔奖章戴到自己的脖子上，比如艾尔逊博士与布兰科博士就可能办到，或是两位博士启发的另外一些人